Prior art focus meter type devices have attempted to measure focus quality by measuring the amount of high spatial frequency content in a viewed scene. An inherent problem with this method lies in the fact that in scenes with a moderate or high detail content, the dynamic range necessary to make an accurate measurement near optimum focus is very difficult to attain. In the alignment of electro-optical systems containing a television (TV) or forward looking infrared (FLIR) sensor several steps are required by an operator relating to the focusing of the system optics and the focusing of the camera electron beam. These adjustments are usually done by a technician watching a TV image of a resolution chart and the results are somewhat subjective in nature.